1. Field of the Invention
The present invention relates to an information recording/reproducing apparatus for recording information on, e.g., an optical disk in accordance with a mark interval recording scheme or a mark length recording scheme, and reproducing information recorded in accordance with the mark interval or mark length recording scheme.
2. Description of the Related Art
An optical disk apparatus as a conventional optical information recording/reproducing apparatus performs mark interval (pit position) recording as a scheme of recording digital data (recordings data) on a recording medium, e.g., an optical disk.
That is, in the mark interval recording scheme, information is recorded by means of the length of the pit-to-pit intervals.
Conventionally, mark interval (pit position) recording is performed as a scheme of recording information on a recording medium. Along with a development in a recording medium suitable for higher-density recording and in the scheme of recording information on the recording medium, mark length recording is becoming possible as a recording scheme.
That is, in the mark length recording scheme, pits having different lengths are formed, and information is recorded by means of the pit lengths and the lengths of the spaces between pits.
Theoretically, the mark length recording scheme has a recording density twice that of the conventional mark interval (pit position) recording scheme. However, due to the different recording schemes, an information recording/reproducing apparatus employing the mark length recording scheme cannot read information recorded on a recording medium in accordance with the conventional mark interval (pit position) recording scheme. Thus, compatibility cannot be obtained.
Hence, an information recording/reproducing apparatus that can record and reproduce information on and from both a recording medium of the conventional mark interval (pit position) recording scheme and a recording medium of the mark length recording scheme that enables a higher-density recording is developed.
In this information recording/reproducing apparatus, the signal processing speeds are different between the mark interval recording scheme and the mark length recording scheme, and each recording scheme requires separate signal processing circuits, e.g., a signal amplifier, a demodulation circuit, a modulation circuit, an error correction circuit, a buffer memory, and an interface circuit.